540 CENOZOIC TIME. 



ternary, when glaciers and icebergs prevailed vastly beyond their ex- 

 isting limits, in itself suggests that the epoch was one of some eleva- 

 tion beyond the present, over the Drift or cold latitudes. 



(2.) The occurrence of fiords only in Glacial latitudes is further 

 reason in favor of the supposed elevation ; and of Europe as well as 

 America. They are positive evidence that, in the era when they were 

 made, the land stood above its present level, and high enough above to 

 allow of their having been excavated, to their bottoms, by the flow 

 along them of fresh water or fresh water and ice — for they are val- 

 leys of erosion. They may have been begun in earlier periods, 

 and have been partly finished in the Cretaceous and Tertiary ; but the 

 almost precise identity of Glacial and fiord latitudes over the globe 

 make it a reasonable supposition that the Glacial era did the finishing 

 work, through the increased elevation of northern lands. 



(o.) This argument from fiords is corroborated by the facts con- 

 nected with the depth of river valleys, mentioned on the preceding 

 page ; and similar facts might be gathered from Europe. 



Further, there is evidence, as shown by F. H. Bradley, that waters 

 from Lake Michigan, in some era, cut a channel from the south end 

 of the lake southwestward to the Mississippi, following a course south 

 to the north line of Iroquois County, Illinois, and thence southwest 

 through Champaign and McLean counties, — the western margin of 

 the trough being well marked by buried escarpments, in some places 

 two hundred feet or more in height. Lake Erie, in like manner, has 

 been found, by G. K. Gilbert, to have discharged southwestward along 

 the course of the Maumee, and not by overflow merely, but by a strong 

 current which cut its trough. The under-sea course of the Hudson 

 River channel has been pointed out on page 423 ; and there is a simi- 

 lar one, though less perfect, for the Connecticut outside of Long Island 

 Sound. Such facts are explained only on the ground of a former ele- 

 vation of the continent to the north ; and the Glacial era is the most 

 probable time of its occurrence. "With an elevation of but two hun- 

 dred feet along Southern New England, Long Island Sound would 

 have been for the most part a fresh-water channel, tributary to the 

 prolonged Connecticut. 



(4.) The Atlantic coast of North America, to the north of Cape 

 Cod, was higher than now during the Cretaceous and Tertiary eras, as 

 is shown by the absence of seashore deposits of these eras. The 

 Tertiary was an era of extensive mountain elevation, and of the cool- 

 ing of climate, both increasing to the end ; and it is probable that the 

 elevation to the north reached its extreme just after the Tertiary, in the 

 Glacial era, when the cooling of the climate also reached its maximum. 



(5.) The height required for the ice-surface, over the Canada water- 



